Costa Coffee has received a string of damning reports from recent hygiene inspections, making it the major high street coffee chain with the most stores rated less than satisfactory.

According to figures obtained by the Daily Mail, 23 stores received two stars or less on the Scores on the Doors website.

Costa Coffee’s managing director Jim Slater said hygiene failings were immediately acted upon and that environmental health office (EHO) figures showed that 98% of the chain’s stores scored good to very good in inspections.

Among the worst finds were mouse droppings and a dead mouse which had lurked in the back room for some time at a Costa next to St Paul’s Cathedral, London. Paninis were also at risk of contamination with the potentially deadly clostridium botulinum bacteria in the Costa at the Royal Hampshire County Hospital.